The rapid development of portable electronic devices is increasing the demand for secondary batteries. In particular, the trend toward smaller, lighter, thinner and more compact portable electronic devices is continuously requiring the introduction of high-energy density batteries as well as inexpensive, safe, and environment-friendly batteries.
A lithium-sulfur battery uses active materials that are inexpensive and environment-friendly. In addition, lithium is expected to have a high energy density of 3830 mAh/g, and sulfur is expected to have a high energy density of 1675 mAh/g. Therefore, the lithium-sulfur battery is emerging as the most promising battery that can satisfy the above conditions.
The lithium-sulfur battery is a secondary battery that uses a sulfur-based compound having a sulfur-sulfur (S—S) combination as an anode active material and a carbon-based material, in which insertion and removal of alkali metal such as lithium or metal ions such as lithium ions occur, as a cathode active material. During a reduction reaction (during discharge), the S—S combination is broken, thereby reducing the oxidation number of S. During an oxidation reaction (during charge), the oxidation number of S increases, thereby forming the S—S combination again. Using this oxidation-reduction reaction, the lithium-sulfur battery stores and generates electrical energy.
The lithium-sulfur battery has an energy density of 3830 mAh/g when using lithium metal as the cathode active material and has an energy density of 1675 mAh/g when using elemental sulfur (S8) as the anode active material. Therefore, the lithium-sulfur battery is the most promising battery in terms of energy density among batteries developed so far. In addition, a sulfur-based material used as the anode active material is an inexpensive and environment-friendly material.
However, there have been no successful examples of commercializing a lithium-sulfur battery system. The failure to commercialize a lithium-sulfur battery is due to a low utilization rate of sulfur when sulfur is used as an active material. Here, the utilization rate of sulfur is represented by a ratio of the amount of sulfur that participates in an electrochemical oxidation-reduction reaction within a battery to the amount of sulfur input. The low utilization rate of sulfur results in a very low battery capacity in reality, compared with a theoretical battery capacity.
In addition, in the lithium-sulfur battery, polysulfide melts out from an anode and moves between the anode and a cathode during charge or discharge. This shuttle phenomenon can affect capacity and cycle characteristics.
Aspects of the present invention provide a need in the art for a method of fabricating an anode for lithium-sulfur batteries, the anode capable of improving the shuttle phenomenon of a lithium-sulfur battery.
Aspects of the present invention also provide a need in the art for a lithium-sulfur battery including an anode fabricated using the method.
However, aspects of the present invention are not restricted to the one set forth herein. The above and other aspects of the present invention will become more apparent to one of ordinary skill in the art to which the present invention pertains by referencing the detailed description of the present invention given below.